Optical waveguide directional couplers couple light beams of different wavelengths to an optical fiber and divide light from the optical fiber into light beams of different wavelengths.
An optical waveguide directional coupler includes a base and an optical waveguide formed in the base. In order to change the direction of the light beams passing through the optical waveguide, the optical waveguide is designed to be bent with a radius of curvature. However, if the radius of curvature is insufficient, the scatting loss of the light beams increases. If the radius of curvature is excessive, though the scatting loss of the light beams decreases, the length of the optical waveguide increases.
Therefore, it is desirable to provide an optical waveguide directional coupler and a method for making same, which can overcome or alleviate the above-mention problems.